Dhoni, who announced his retirement from international cricket last month, is preparing to take part in his 13th successive IPL for Chennai Super Kings.
The 39-year-old captained CSK to the final during IPL 2019 but Pietersen is concerned about his form and mindset after such a long break.
Dhoni has not played a competitive match since July 2019, when India were knocked out of the World Cup by eventual runners-up New Zealand.
‘MS Dhoni announced his international retirement a few weeks ago, so it’s going to be interesting to see how he goes in this competition,’ former England batsman Pietersen told Betway.
‘I know how passionate he is, how dedicated he is and how much he loves the Chennai Super Kings.